DE1594370B2 - MINERAL OR SYNTHETIC OIL - Google Patents

Description

in which R is an alkyl radical with 1-20 carbon atoms, an alkoxyalkyl, aryl or an aralkyl radical, R2 is a Alkyl radical and R3 denotes an alkyl radical or a hydrogen atom, where R2 and R3 together Contain 8-24 carbon atoms, and optionally one or more secondary aromatic amines, which contain two aromatic rings bonded directly to the nitrogen atom, and optionally a rust inhibitor, a sludge dispersant, a metal deactivator and a pressure receptivity improving agent.

2. Lubricant according to claim 1, characterized in that it is used as the pressure absorption capacity improving agents a chlorinated di- or polyphenyl or a mixture of these compounds contains, which have at least two chlorine atoms per benzene nucleus, the chlorine atoms with the Carbon atoms of the aromatic nucleus are directly connected.

3. Lubricating oil according to claim 2, characterized in that it is the chlorinated di- or polyphenyl in an amount of 0.5 to 10% by weight, preferably 1.0 to 5.0% by weight, based on the total mixture, contains.

4. Lubricating oil according to claim 1, characterized in that it is 0.05 to 0.2% benzotriazole and 0.005 contains up to 0.05% of an aliphatic dicarboxylic acid with 6 to 10 carbon atoms.

45

The present invention relates to a mineral or synthetic lubricating oil.

The lubricating oil is characterized in that it consists of a larger proportion of a mineral or synthetic lubricating oil and a smaller proportion of a phenothiazine derivative of the general formula

55

60

CH ₂ OR

in which R is an alkyl radical with 1-20 carbon atoms, an alkoxyalkyl, aryl or aralkyl radical, R _{2 is} an alkyl radical and R _{3 is} an alkyl radical or a hydrogen atom, where R ₂ and R3 together contain 8-24 carbon atoms, and optionally one or more secondary aromatic amines which contain two aromatic rings bonded directly to the nitrogen atom, and optionally a rust inhibitor, a sludge dispersant, a metal deactivator and an agent which improves the pressure absorbency.

The agent improving the pressure receptivity is preferably a chlorinated di- or polyphenyl or a mixture of these compounds which have at least 2 chlorine atoms per benzene nucleus, the Chlorine atoms are directly linked to the carbon atoms of the aromatic nucleus. The chlorinated Di- or polyphenyl is preferably in an amount of 0.5 to 10% by weight, preferably 1.0 to 5.0% by weight, based on the total mixture contained in the lubricating oil.

According to a preferred embodiment of the invention Lubricating oil it contains 0.05 to 0.2% benzotriazole and 0.005 to 0.05% of an aliphatic Dicarboxylic acid with 6 to 10 carbon atoms.

It has surprisingly been found that the phenothiazine derivatives of the above general formula in lubricating oils on a mineral or synthetic basis of various types, eg. B. on the basis of known neutral organic dicarboxylic acid diester, or on the basis of so-called "hindered ester" that f from dihydric or polyhydric alcohols derived which contain no hydrogen atoms in ^ position to the hydroxyl groups, are effective antioxidants. They are also effective antioxidants in lubricating oils based on polyglycol ethers.

The phenothiazine derivatives are effective antioxidants for synthetic ones even when used alone Ester-based lubricating oils. Their effectiveness can, however, be increased considerably if them together with one or more secondary aromatic amines having two aromatic groups be applied to the nitrogen atom, in which case both additives have a synergistic effect Oxidation at elevated temperatures result.

Phenothiazine itself has previously been used with success as an antioxidant in synthetic gas turbine lubricating oils used on an ester basis, but it has the disadvantage that it forms insoluble oxidation products, which separate out as sludge. This "phenothiazine contamination" was often the factor that reduced the service life of an oil limited in operation. From US Pat. No. 2,781,318, the use of (, Phenothiazine derivatives with alkyl substituents on the aromatic nuclei for the production of lubricant preparations known. The compounds preferably used therein are dioctylphenothiazines. In US Pat. No. 2,930,758 is also already the combination of a phenothiazine with an amine, the Has antioxidant properties, described. Here, the phenothiazine can, for example, am Nitrogen atom carry an alkyl group.

Finally, N-alkylated phenothiazines are already known from British patent specification 8 73 066 which can optionally be substituted on the aromatic nuclei.

However, all of these lubricant preparations show at elevated temperatures under the action of oxygen a tendency towards soiling, with an increased increase in viscosity being noted at the same time. On the other hand The lubricating oils according to the invention offer significant advantages over those with conventional additives. So has been found, for example, through experiments that a lubricating oil with N-methylphenothiazine as an additive an oxidation test significantly worse results with regard to the degree of soiling and the

Increase in viscosity with the same loss of fluid and approximately the same increase in acidity compared to such Preparation provided the N-isobutoxymethyl-S ^ -dioctylphenothiazine contained. Although both phenothiazine compounds have similar antioxidant properties, the lubricating oil according to the invention remained clear, while the conventional phenothiazine as an additive containing lubricating oils are heavily soiled. By adding the phenothiazine derivatives of the above general formula, lubricating oils are obtained which are different from the previously known preparations by their insensitivity to oxidative influences and by an extraordinarily diminished one Distinguish the formation of insoluble suspended matter and deposits in operation.

The problem of "phenothiazine contamination" of lubricating oils could surprisingly be solved by using the above-mentioned phenothiazine derivatives instead of phenothiazine itself. In order to achieve adequate oxidation resistance of the make-up oil at temperatures such as occur in aircraft gas turbines, these compounds can be used together with other additives, in particular with one or more secondary aromatic amines. An example of a combination synergi- ² S cally acting from antioxidants of this type is the combination of 3,7-dioctylphenothiazine with ρ, ρ'-dioctyldiphenylamine or naphthylamine, phenyl-a-.

Synthetic lubricants diester which contain combinations of additives of the type referred to above, have very satisfactory properties at the maximum approach oil temperatures from 177 to 190.5 ⁰ C and are extremely clean in operation. However, when the supersonic aircraft went into operation and the resulting considerably higher maximum oil temperature (e.g. 232 ° C for the so-called "Type II" oils), lubricating oils with a higher thermal and oxidation resistance were required.

It has now been found that the above-mentioned derivatives, when used together with secondary aromatic Amines of the type mentioned above are used in "sterically hindered ester" base oils, Lubricating oils provide superior resistance to oxidation at temperatures in the region of 222 ° C compared to lubricating oils containing phenothiazine or known phenothiazine derivatives.

Although compounds of the general formula given above, in which the benzene nuclei are unsubstituted are very effective antioxidants and the phenothiazine in the temperature range from 204 to 232 ° C are superior, but they also tend to form sludge under oxidizing conditions, since at the same degradation products as with phenothiazine itself are formed over long periods of time.

On the other hand, phenothiazine derivatives of the above general formula are good in lubricating oils Oxidation resistance and do not tend to form sludge. The phenothiazine derivatives mentioned above can especially in lubricating oils based on synthetic organic carboxylic acid esters, which are used for the ' Use as high temperature gas turbine lubricating oils are suitable to be included. Accordingly, includes Invention, in a preferred embodiment, a lubricating oil with a larger proportion of one synthetic, organic lubricating oil based on neutral organic carboxylic acid esters, the esters are preferably those of the "sterically hindered ester" type and a smaller proportion of two Additions (a) and (b), where the. Additive (a) a phenothiazine derivative of the formula given above, and additive (b) is a secondary aromatic amine which is two immediately adjacent to the nitrogen atom contains linked aromatic residues. The preferred secondary aromatic amine is phenyl-a-naphthylamine used. However, other amines can optionally also be used.

Preferably, as additive (a) an N-alkoxymethyl or N-cycloalkoxymethyl derivative of 3,7-dioctylphenothiazine, which is derived from a primary alcohol ROH having 1-20 carbon atoms in the remainder R, and as additive (b) phenyl-oc-naphthylamine used.

Examples of the phenothiazine derivatives mentioned above are:

Nl, 3-dimethyl-butoxymethyl-phenothiazine, N-methoxy-methyl-3-n-butoxy-phenothiazine; Nn-hexoxymethyl-3-n-decoxyphenothiazine ■■■, -SJ-dioctyl-phenothiazine Nn-hexoxymethyl-3,7-dioctyl-phenothiazine Nn-octoxymethyl-3,7-dioctyl-phenothiazine Nn-decoxymethyl-Sy-dioctyl-phenothiazine; Nn-dodecoxymethyl-SJ-dioctyl-phenothiazine Nn-hexadecoxymethyl-SZ-dioctyl- _; ;

phenothiazine .-- ...

N-n-octadecoxymethyl-SJ-dioctyl-, *

phenothiazine ■

N-Oleoxymethyl-SJ-dioctyl-phenothiazine .. ■ N ^^^ - trimethylpentoxymethyl-;

3,7-dioctyl-phenothiazine ■ ': _; ,

N-S.S.S-trimethyl-hexoxymethyl- .....: 3,7-dioctyl-phenothiazine:. .

N-Cyclohexoxymethyl-SJ-dioctyl-phenothiazine N-Benzyloxymethyl-3,7-dioctyl-phenothiazine N-Phenoxymethyl-3,7-dioctyl-phenothiazine N-j8-ethoxyethoxymethyl-3,7-dioctyK; phenothiazine

N-methoxymethyl-3-monooctyl-phenothiazine N-methoxymethyl-3,7-dibutyl-phenothiazine N-methoxymethyl-mono-octyl-. ■■:. ·. 6,7-benzophenothiazine.
Examples of additives (b) are:
Phenyl-a-naphthylamine. . _:

Phenyl-j3-naphthylamine ■

ρ, ρ-dioctyl-diphenylamine,:

p-monooctyl-diphenylamine
mixed octylated diphenylamines mixed heptylated diphenylamines p-isopropyldiphenylamine
pn-butoxydiphenylamine
Diphenyl-p-phenylene-diamine
pn-octoxy-diphenylamine ''

pn-decoxy-diphenylamine
pn-dodecoxy-diphenylamine:

p-n-hexadecoxy-diphenylamine p- (3,5,5-trimethyl-hexoxy) -diphenylamine. p-n-octoxy-phenyl-jS-naphthylamine p, p'-di-n-decoxy-diphenylamine 2,5-dimethoxy-4'-n-octoxy-diphenylamine m-n-hexadecoxy-diphenylamine p-n-decoxy-phenyl-jS-naphthylamine. If it is desired that the lubricating oil be one that is suitable for use at make-up oil temperatures of

about 232 ° C is suitable, is preferred as an ester So-called »sterically hindered ester« used, that of primary monohydric or polyhydric alcohols is derived, i.e. alcohols with 2 to 10 or more OH groups in which no hydrogen atoms with the ^ -Carbon atoms are connected.

These alcohols, which contain one or more OH groups, have the formula:

R ₃ ■:
-CC-CH ₂ OH

R ₄

in which R ₃ and R 4 are alkyl, hydroxyalkyl or etherified hydroxyalkyl radicals. These "hindered esters" have been found to have better thermal stability compared to the normal synthetic diester-type lubricating oils. Examples of "hindered esters" are:

Di (2,2,4-trimethylpentyl) sebacate

Di (2,2,4-trimethylpentyl) azelate

Trimethylolethane tricaproate

Trimethylol propane trivalate

Trimethylol propane tri-n-heptanoate

Trimethylol propane tri-pelargonate

Trimethylol propane tricaprate

Pentaerythritol tetracaproate

Dipentaerythritol hexacaproate

2-methyl-2-ethyl-propane-1: 3-diol-

dipelargonate

complex ester made from trimethylol propane (2 moles), carponic acid (4 moles) and sebacic acid (1 mole);

complex ester made from trimethylol propane (2 moles), butyric acid (4 moles) and azelaic acid (1 moles);

complex ester made from neopentyl glycol (1 mole), sebacic acid (2 moles) and 2,24-trimethylpentanol (2 moles).

Many of the complex "hindered esters" are too viscous to be used as the only lubricating oil for Aircraft gas engines to be used, but they can be mixed with simple »sterically hindered Esters «can be used in an amount of, for example, 1 to 70% by weight.

Optionally, mixtures of mixed esters can be produced by esterification of a sterically hindered one Alcohol can be made with a mixture of acids within a wide range. So became for example trimethylolpropane (0.4 mol) with a mixture of caproic acid (0.5 mol) and capric acid (0.5 mol) esterified. The product was further esterified with sebacic acid (0.1 mol) to give a mixture of to yield complex and simple esters. The product had a viscosity of 6.88 cSt at 99 ° C and a pour point of -51.5 ° C.

With many types of "sterically hindered esters", esters of trimethylolpropane or are preferred Pentaerythritol is used with straight-chain monocarboxylic acids containing 4 to 10 carbon atoms. One A very suitable base fluid contains a major proportion of a mixture of esters of trimethylolpropane with straight-chain monocarboxylic acids with 4 to 9 carbon atoms together with a smaller one Proportion, preferably from 5 to 30%, and a mixture of esters of dipentaerythritol with straight-chain Monocarboxylic acids containing 2 to 10 carbon atoms. It has been found that lubricating oils on the basis of such mixtures have a lower tendency to sludge formation than lubricating oils which are completely based on trimethylolpropane ester. For applications where the lubricating oil is not exposed to temperatures above approximately 177 ° C, The lubricating oils according to the invention can be based on a synthetic lubricating oil, one or the other includes several of the conventional types of diesters. Examples of diesters that can be used are:

Di-2-ethyl-hexyl-sebacate
Di-3,5,5-tri-methyl-hexyl-sebacate, di-iso-octyl-sebacate

Die-2-ethyl-azelate
Di-iso-octyl azelate
Di-iso-octyl adipate
Di-iso-decyl adipate
Di-iso-tri-decyl adipate.

These lubricating oils that can be used at these temperatures may, 1 to 40 wt .-% of a substantially water-insoluble polyoxyalkylene Γ lenglykoläthers included.

Such polyoxyalkylene glycol ethers have the general formula

RO (R ₁ O) _n -R ₂

where R is an alkyl group, Ri is an alkylene radical, R _{2 is} a hydrogen atom or another alkyl group and η is an integer. _{R t} preferably represents a propylene radical or a mixture of propylene and ethylene radicals, it being possible to obtain suitable products by reacting propylene oxide or a mixture of propylene and ethylene oxides with an aliphatic monohydric alcohol or a monoether of a glycol. The polyoxyalkylene chain can therefore be composed of various alkylene radicals Ri. In the case of the preferred ethers in which R _{2 is} hydrogen, it is preferred if at least a proportion of propylene groups is present in the polyoxyalkylene chain in order to obtain essentially water-insoluble products.

Synthetic lubricating oils are particularly preferred,

those made of mixed polyoxypropylene glycol ethers with (_ consist of one free hydroxyl group per molecule. For example, there are two such mostly viscous lubricating oils particularly suitable for use in lubricating oils that are designed to meet the requirements of the British regulation D. Eng. Meet R. D. 2487.

The lubricating oils of the invention can contain small amounts of benzotriazole and small amounts of Dicarboxylic acid, such as sebacic or azelaic acid, contain.

Smaller amounts, for example up to 20% by weight, based on the lubricating oil, can optionally be used Polyphenyl ethers are used; such compounds can be used especially in high temperature lubricating oils.

In certain cases it may also be desirable to add one or more additives for the lubricating oil Use to increase the pressure absorption capacity of the lubricating oil.

The lubricating oils according to the invention can also be copolymers as additives with sludge-dispersing agents Features included. Examples of such additives are copolymers of alkyl methacryl bututene, z. B. lauryl or higher methacrylates or

Mixtures of such methacrylates with N-vinylpyrrolidone and copolymers of long-chain alkyl fumarates with vinyl acetate and N-vinylpyrrolidone. These copolymers not only act as sludge dispersants, but in some cases also give a synergistic effect with the antioxidants. According to the invention, these copolymers can be obtained in amounts of about 0.2 to 1.5% by weight on the lubricating oil.

A preferred lubricating oil according to the invention is one which contains an ester of the general formula:

CH ₂ OOC R '

CH ₃ CH ₂ C-CH ₂ OOC R "

CH ₂ OOC R '"

contains, in which R ', R "and R'" are identical or different, straight or branched chain alkyl with an average of 6 to 9 carbon atoms, wherein the ester at 99 ⁰ C a viscosity of about 3.0 to 5, and at a OcStaufweist Storage at -40 ^° C. for at least 72 hours shows no crystallization. These esters contain an N-cycloalkoxymethyl-SJ-dioctyl-phenothiazine dissolved in an amount sufficient to give a content of 0.04 to 0.15% sulfur and further 1.5 to 2.5% phenyl-a- naphthylamine.

In addition to the antioxidants, in which, according to the above general formula, the aromatic nuclei are unsubstituted, a sludge dispersant is still used. But are phenothiazine derivatives of the above general formula used, in which the aromatic nuclei are substituted by alkyl groups are substituted having a total of 8 to 24 carbon atoms, then the use of sludge dispersants is superfluous. This is a major benefit as the sludge dispersants through Shear and thermal degradation reduce the viscosity of the lubricating oil. The following examples explain The invention.

example 1

96.25% ester B

1.5% N-ethoxymethyl-sy-dioctylphenothiazine

2.0% phenyl-a-naphthylamine

0.2% benzotriazole

0.05% sebacic acid

Ester B is di (2,2,4-trimethylpentyl) azelate.

Example 2

62.0% ester A.

37.5% Ester B 0.3% N-hexoxymethyl-SJ-dioctylphenothiazine

Ester A is di (2,2,4-trimethylpentyl) sebacate.

B e i s ρ i e 1 3

60.0% ester A.

37.3% ester B

0.5% butylene bis (2,4-di-t-butyl-phenol)

0.2% N-methoxymethyl-sy-dioctylphenothiazine

This lubricating oil is of a type suitable for use as an ashless dispersing oil for Piston aircraft engines is suitable.

B e i s ρ i e 1 4

98.69% polyoxypropylene glycol ether (viscosity 38 cSt at 99 ° C)

1.0% N-Cyclohexoxymethyl-Sy-dioctylphenothiazine 0.3% p, p'-Dioctyldiphenylamine
0.01% benzotriazole

This lubricating oil is of a type suitable for use as a synthetic worm gear lubricating oil, according to the SAE 140 viscosity requirements, suitable is.

Example 5

66.25% di (2-ethylhexyl) sebacate

28.0% polyoxypropylene glycol ether

1.5% N-methoxymethyl-3,7-dioctylphenothiazine

1.5% p, p'-dioctyldiphenylamine

2.4% chlorinated diphenyl with 54% chlorine

0.25% mineral oil solution with 20% by weight calcium petroleum sulfonate

This lubricating oil is of a type useful as a gas turbine lubricating oil for aircraft engines and had a viscosity of about 7.5 cSt at 99 ° C.

Examples

85.39% ester A
10.0% ester C

2.5% phenyl-a-naphthylamine

2.0% N-n-decoxymethyl-SJ-dioctylphenothiazine 0.1% benzotriazole

0.01% sebacic acid

Ester C was a dipentaerythritol ester of mixed straight chain carboxylic acids of 2 to 10 (average 6) carbon atoms.

This lubricating oil is of a type useful as a gas turbine lubricating oil for aircraft engines is. .

Example 7

70.89% ester A
25.0% ester C

2.5% phenyl-a-naphthylamine

1.5% N-methoxymethyl-3,7-dioctylphenothiazine 0.1% benzotriazole

0.01% sebacic acid

This lubricating oil was the regulations of the Aviation D. Eng. R. D. 2497 just.

Example 8

97.25% trimethylolpropane tri-n-heptanoate 2.0% phenyl-a-naphthylamine
0.75% methoxymethyl-SJ-dioctylphenothiazine.

This oil had a viscosity of about 4 cSt at 99 ⁰ C and corresponds to a synthetic gas turbine lubricating oil of relatively low viscosity which is able to operate at a maximum of 204 ⁰ C Ansatzöltemper.aturen.

The lubricating oils of Examples 1 and 6 through 8 are particularly preferred high temperature synthetic gas turbine lubricating oils.

The thiazine derivatives described above can be prepared in a simple manner by a

609 547/477

ίο

correspondingly substituted thiazine of the general formula

■ η with a suitable alcohol or phenol ROH and Formaldehyde under relatively mild conditions. A buffer such as sodium dihydrogen phosphate dihydrate can be used to advantage in some cases. The following examples explain iie production of typical thiazine derivatives, which are used as \ ntioxidants in the inventive Lubricating oils can be used.

Production of
Nn-decoxymethyl-SJ-dioctylphenothiazine

3,7-dioctylphenothiazine (423 g, 1 mole), n-decanol g, 1.4 mol), a 51% solution of formaldehyde η methanol (84 g, 1.4 mol) and sodium dihydrogen phosphate dihydrate (32 g) were refluxed for 1 hour. The reaction mixture was in

etrolether dissolved and washed with water. the

15th

20th

25 dried petroleum ether layer was evaporated and. slowly pour the residue in while stirring vigorously Poured methanol. The product was filtered off, sucked dry and recrystallized from isopropanol.

500 g (85%) of a solid white product, melting point 91 to 93 ^° C., were obtained.

Production of
N-methoxymethyl-SJ-dioctylphenothiazine

3,7-dioctylphenothiazine (423 g, 1 mol), methanol (2 I), 40% aqueous formalin (11.13 mol) and sodium dihydrogen phosphate dihydrate (10 g) was refluxed for 4 hours. The hot solution was filtered off and the solid product insoluble in methanol separated; Mp. 150 to 160 ° C.

After recrystallization from acetone, 328 g (70%) of a solid product, melting point 173 to 174.5 ° C, severed.

Other thiazine derivatives can be prepared in a similar manner, using the working procedures only differ slightly depending on the physical properties of the products. In the The following table shows the properties and yields of a number of those obtained in this way Connections put together.

ibelle

drawing substituents
R2

R3

Recrystallization Solvent

yield

*) 7-t-CsHi7

7-t-CsHi7
7-t-CsHi7
7-t-CsHi7
7-t-CsHi7
7-t-CsHi7
7-t-CsHi7
7-t-CsHi7
7-t-CsHi7
7-t-CsHi7
7-t-CsHi7

7-t-CeHi7

7-t-CsHi7

7-t-CsHi7

7-t-CsHi7

7-t-CsHi7

7-t-CsHi7

lelle (continued)

3-t-CsHi7
3-t-CsHi7
3-t-CsHi7
3-t-CsHi7
3-t-CsHi7
3-t-CeHi7
3-t-CsHi7
3-t-CsHi7
3-t-CsHi7
3-t-CsHi7
3-t-CsHi7

3-t-CsHi7

3-5-CsHi7l

3-5-CsHi7l

3-5-CsHi7l

3-5-CsHi 7l

3-5-CeHi7l

3-nC4H9O

3-n-CioH2iO

CH3

C2H5

n-C4H9

n-C6Hi3

n-CioH2i

n-CieH37

n-CisH35 *)

i-CsHi? *)

i-CsHi?

1-C9H19 *)

1-C10H21

1-C13H27 *)

CeHn

CeHs

C6H5CH2

C2H5OC2H4 *)

CH3

n-CioH2i

n-CeHi3

acetone 70 isopropanol 98 - 57 - 76 Isopropanol 92 - 76 80 Isopropanol 53 Isopropanol 62 52 102 (little residue. Flow. 1-C10H21OH) - 78 Heptane 58 Heptane approx. 5 - 76 acetone 75 - 75 - 88 77

Melting point Analytical data N S. theoretical Lot (%) N S. H- found (%) C. H ("C) C H

173-174.5 76.3 9.95 3.09 6.88 77.6 9.72 3.00 6.86 157-158 - - 2.98 6.74 - - '2.91 6.65 132-134 - - 2.73 6.48 - - 2.74 6.28 128-130 - - 2.37 D.97 - - 2, bl 5.96 90-93 78.5 10.6 2.62 5.52 78.9 10.7 2,3b 5.39 61- 67 79.0 11.06 2.04 4.56 80.10 11.20 1.99 4.54 wax 79.3 11.01 2.05 4.37 80.0 10.9 1.99 4.54

Melting point 11th data H 15th 94 370 theoretical 12th N S. '«) 10.32 C. 2.48 5.65 Γ Q Analytical 10.19 78.4 2.48 5.65 89-92 found ("/ - 78.4 Lot (%) 2.42 - continuation 135-137.5 C. - - ■ H 2.36 5.39 Be 127-135 78.0 - N S. - 10.05 2.21 - drawing 102 78.6 9.68 2.61 6.03 - 10.05 2.62 5.98 tion fluid - - 2.42 5.86 79.0 - 2.64 6.04 8th 146-150 - 9.38 2.72 - _ 2.57 5.89 9 142-148 - - 2.66 5.76 79.6 - 2.66 6.08 10 104-108 78.8 - 1.97 - __ 9.98 3.95 9.01 11th 45-50 - 9.41 2.42 5.88 - - 3.17 7.25 12th approx 45 81.2 - 2.56 6.56 73.3 9.06 3.00 6.85 13th fluid - 2.71 6.03 - - 14th fluid - 2.49 6.29 - 15th 74.1 3.96 9.16 8.88 16 - 3.49 7.96 - 1 3.14 7.63 1 1

Further meanings of the remainder R:

7R = oleyl,

8R = 2-ethylhexyl,

9R = 2,2,4-trimethylpentyl,
10R = 3,5,5-trimethylhexyl,

11 R = derived from mixed-branched primary decanols, 12R = derived from mixed-branched primary tridecanols, 16R = CH3CH2OCH2CH2.

In cases where no recrystallization solvent is specified, the substance crystallized immediately from methanol and was filtered off.

Other compounds that can be prepared in the same way are e.g. B. Methoxy-methyl-monooctyI-6,7-benzophenothiazine and methoxymethylmonooctyl-8,9-benzophenothiazine.

In order to show the superiority of the lubricating oils according to the invention over those that have already were known, in particular from US Pat. No. 2,781,318, the following experiments were carried out.

Initially, lubricating oils were produced with the following composition:

Pentaerythritol tetraester 96.74% Phenyl-a-naphthylamine 1.0% p.p'-di-octyl-diphenylamine 1.0% o-methylene-bis-2,4-di-. tert-butyl-phenol 0.4% Benzotriazole 0.05%

Sebacic acid 0.01% Substituted Phenothiazine compounds 0.8%

The following were used as substituted phenothiazine compounds:

In lubricating oil A

N-isobutoxymethyl-3,7-di-octylphenothiazine

(= Lubricating oil according to the invention)
In lubricating oil B

N-methyl-phenothiazine (= state-of-the-art lubricating oil)

The lubricating oils were tested with the aid of an oxidation test in which air at 230 ° C. was passed through for 70 hours Lubricating oils was blown through, tested.

The results are shown in the following table:

Tabel

Lubricating oil

Ver

volatile

loss

Increase in
Viscosity at
99 ° C

Insoluble portion Increase in acidity

A.
B.

29%
28%

74%
86%

0.04%

5.6 mg / KOH per g
3.9 mg / KOH per g

The lubricating oil B was contaminated, as can be seen from the higher percentage of insolubles, whereas Lube Oil A was clean. Similar lubricating oils in which 3,7-dioctyl-phenothiazine is used as substituted phenothiazine was used resulted in a viscosity increase of almost double.

Further experiments were carried out with lubricating oils in which phenothiazine compounds were substituted one time N-n-decoxymethyl-SJ-dioctylphenothiazine (= lubricating oil according to the invention) and the other time 3,7-dioctyl-phenothiazine (= lubricating oil according to the state of the art).

The other components of the lubricating oils were the same as those in the lubricating oils described above Experiments with the exception that this instead of p, p'-dioctyldiphenylamine 2.0 or 2.5 wt .-% phenyl - «- contained napthylamine.

A modified Baber test, which is described below, was carried out with these lubricating oils will.

The Babertest is an extreme oxidation test in which air is blown at a rate of about 196 1 per Hour through 350 ml of the lubricating oil to be tested, which is in a wide tube with a diameter of 64 mm was blown. The pipe was equipped with a side arm at the head from which volatile oxidation products were distilled.

In the experiments used here, a steel sheet with a total surface area was used as the catalyst 5.08 cm used.

Ester A, also used in some examples, was used as the base oil.

It was found in this test that both

the lubricating oil containing 2.0% phenyl-a-napthylamine, as well as the 2.5% phenyl-ix-napthylamine contained, the increase in viscosity of the lubricating oil according to the invention with a content of phenothiazine im investigated range from about 0.5 to 3.0% lower, sometimes even quite significantly lower than in the lubricating oil according to the prior art with a corresponding phenothiazine content.

Compared to the lubricating oils according to the invention are

ίο similar worse results with lubricating oils too expect to contain N-phenylphenothiazine instead of 3,7-dioctyl-phenothiazine.

Claims (1)

Patent claims: 1. Lubricating oil, consisting of a larger proportion of a mineral or synthetic Lubricating oil and a smaller proportion of a phenothiazine derivative of the general formula CH ₂ OR